Computed tomographic (CT) scans are often obtained before mandibular distraction osteogenesis in patients with isolated Pierre Robin sequence. There is concern regarding the risk of radiation exposure from CT in children.To evaluate whether preoperative CT is necessary for adequate airway, feeding, and aesthetic outcomes following mandibular distraction with external distraction devices in infants with isolated Pierre Robin sequence.In a retrospective review of medical records, infants who underwent mandibular distraction between January 1, 1998, and September 30, 2014, at 2 tertiary childrens hospitals were identified using procedure codes. Data analysis was conducted December 1, 2014, to March 31, 2015. Fifty-two patients fit the inclusion criteria of isolated Pierre Robin sequence or Stickler syndrome, of being younger than 9 months at the time of distraction, and of use of external distractors. Forty-two of these infants did not receive preoperative CT imaging.Mandibular distraction osteogenesis for isolated Pierre Robin sequence or Stickler syndrome.Number of infants who were able to avoid tracheostomy or achieve decannulation, who were able to avoid placement or achieve removal of a gastrostomy tube, and in whom there were no intraoperative complications, no open-bite deformity, no malocclusion, no asymmetry, and no postoperative complications.In comparison with the 10 infants who underwent preoperative CT, all 42 of the infants (100%) who did not receive preoperative CT imaging successfully avoided tracheostomy or achieved decannulation (P=.04) and 40 patients (95%) did not require placement of a gastrostomy tube or were able to undergo gastrostomy tube removal postoperatively (P